Lord Rees of Ludlow: 'I hope that space travel will become cheaper even though it will be riskier'

The Monday Interview: President of the Royal Society

He is Britain's top scientist. The new president of the Royal Society is also Astronomer Royal, master of Trinity College, Cambridge and renowned cosmologist whose deep thoughts frequently turn to deep space, dark matter and the dawn of creation.

Lord Rees of Ludlow, known to the many readers of his science books as Martin Rees, is also something of a thought-provoking populariser. He believes that a butterfly poses more daunting scientific problems than a star and that the search for extraterrestrial intelligence is well worth the effort.

He has advocated the exploration of space by a new generation of adventurers willing to take risks by travelling cheap, and is against the kind of costly manned exploration funded by risk-averse governments. He favours fleets of miniature robotic probes to explore the planets rather than a manned mission to Mars and thinks the multibillion-dollar International Space Station is a "turkey in the sky".

Lord Rees the cosmologist has proposed our universe may be just one of zillions, each with its own set of physical laws, and that the universe we find ourselves living in may, in fact, be a mere computer simulation built by a race of super-intelligent beings.

He believes there is a 50 per cent chance that human civilisation may not survive in its present form by the end of the 21st century, and has warned that a major environmental collapse within the next hundred years carries the same sort of probability as tossing a coin.

Lord Rees the gambler has placed a £1,000 bet that, within the next 20 years, a million people will die as a result of a major man-made biological catastrophe caused either by bio-error or bio-terror. "It is a bet that I very much hope to lose," he says.

"I do think we're entering a phase where science offers unprecedented opportunities. It empowers us far more to do marvellous things in information technology, biology and so on but obviously all these developments have a downside," he says from the splendour of his presidential office overlooking The Mall and St James's Park.

"As my predecessor, Bob May, used to say, quite rightly, we have to decide which doors to open and which to remain closed. The faster science advances, the more choices we have to make of that kind," he says.

The Royal Society was established in 1660 as an intellectual talking shop for the scientific elite of the day, such as Christopher Wren and Robert Boyle, and, within a year, received its Royal Charter from Charles II. In 1847, the society decided to elect its fellows on the basis of scientific merit alone and this more professional approach led it to become Britain's de facto national science academy. Being elected a Fellow of the Royal Society is said to be the highest accolade a British scientist can receive, short of a Nobel Prize, and each year another 44 people can put the hallowed FRS initials at the end of their name.

Once every five years, the fellows elect their next president, an FRS who then becomes an even more distinguished PRS. There is only one of them, and Lord Rees is him. Past presidents have included some of the most famous men in history, such as Samuel Pepys, Isaac Newton and Ernest Rutherford, and, yes, they have all been men.

Fewer than one in 10 of the 1,400 fellows is a woman but Lord Rees is keen to dispel any notion that the Royal Society is a club of elderly, white gentlemen. He points out that a good proportion of the more recently elected fellows are women. That they are still a minority is a reflection of how few girls take up science at school. He says the society is a modern organisation and he proudly shows off its refurbished offices in Carlton House Terrace, with one of its latest acquisitions, a Damien Hirst donated after the ill-fated attempt to put the Beagle 2 probe on Mars.

"You can see from the buildings that they don't give the aura of a gentleman's club - there's no bar here. The conditions where people work are 21st century, not 18th century," he says.

For a body that is built on unashamed intellectual elitism, one might ask what the society is for in a less deferential age. "The aim of the Royal Society is to support scientific excellence and do what it can to support science, its applications and to engage with the public and policy-makers," Lord Rees explains.

"Our role is to ensure all decision-making is based on the best possible scientific evidence. Awareness of the science tells us where the uncertainties are and I think it's our job to engage and discuss with the wider public and the policy-makers in order that there are as few as possible misconceptions about science."

One of the biggest science issues coming up in 2006 is whether Britain should go ahead with a programme of rebuilding nuclear power stations to replace those that will soon be decommissioned. "I think energy policy is an issue where we have to distinguish getting the science right and erasing misperceptions," he says. One particular misperception he would like to puncture is the idea that nuclear power stations produce more carbon dioxide than they save over their entire life cycle. "That's often stated and that is plainly wrong," he insists.

But what will be the Royal Society's position on nuclear power? "The society hasn't discussed whether to take any stance on that. My personal view, and it is just personal, is I believe nuclear energy should be part of the energy mix in the UK.

"That doesn't mean I believe it has a major worldwide contribution to make to reducing carbon dioxide emissions.

"It is not obvious to me that renewables can take up the slack within the next 20 years if the existing nuclear power stations are decommissioned. I also think there is the energy security issue of not depending too much on gas from overseas sources. But let me emphasise that these are my personal views and currently the Royal Society has no collective view on this particular decision," he says.

As individuals, scientists should be encouraged to get involved in scientific debates affecting society. "Scientists are sometimes rather unwilling to get involved in controversy and I think as individuals they should be getting involved in these debates," he says.

"What went wrong on the GM debate was that it became polarised between the commercial interests and the environmentalists much too early on.

"That's why the stem cell debate was much better handled because the scientists were able to engage with parliamentarians and opinion formers and do this before commercial interests became involved, with the result that the UK has a regime for regulating the use of stem cells which is certainly far better than in the United States and many other countries," he says.

Of course, informed debate relies on an educated, scientifically-literate public. And that requires good science teachers, who are lacking in Britain. "There really is a crisis in terms of high-quality specialist teachers in physics, maths and other specialist subjects," Lord Rees says. "We feel we have a special role in trying to articulate these problems and we'll try to do what we can to get all those concerned to speak with one voice," he says.

As an academic, Lord Rees is well aware of the financial pressures on universities, which have had to cope with a huge increase in students without a commensurate increase in resources. He is particularly concerned with the leading research universities, such as Oxford, Cambridge and Imperial College London.

"The public and the politicians have to appreciate that it is our good fortune in this country to have a number of world-class universities.

"The UK is in a privileged position in having world-class research universities at a level and in a quantity that is unmatched by any other country other than the US and we do need to ensure that is not jeopardised.

"The resources they have are very low compared to their competitors in the US. It's very important we realise we have the option between having a few of our universities that are really world class, or zero," he says.

Nasa spends three or four times as much as the European Space Agency but much of the money goes on the expense of making manned missions as safe as possible. So is he totally against sending people into space?

"As a scientist and practical man I'm against but as a human being I'm in favour," he says. "What I mean is that I hope in the long run that people will go into space but I think that will only be when it can be done much more cheaply by adventurers prepared to take high risks," he says. "I think the style of manned spacecraft which Nasa does, where it's got to be done with very low risks, and therefore very expensive, is so expensive as to be hardly worthwhile."

The CV

* BORN 23 June 1942

* EDUCATION Shrewsbury School; Trinity College, Cambridge

* CAREER

1968: Research fellow, Caltech

1967-69: Fellow, Jesus College, Cambridge

1967-72: Staff, Institute of Theoretical Astronomy, Cambridge

1969-72: Senior research fellow, King's College, Cambridge

1969-70: Member, Institute for Advanced Study, Princeton

1971: Visiting professor, Caltech

1972 and 1988-89: Visiting professor, Harvard University

1973-91: Plumian Professor of astronomy and experimental philosophy, Cambridge University; professorial fellow, King's College, Cambridge University

1977-82 and 1987-91: Director, Institute of Astronomy

1992-2003: Royal Society research professor

1995-: Astronomer Royal

2003-: Professor of cosmology and astrophysics, Cambridge

2004-: Master of Trinity College, Cambridge

Nov 2005-: President of the Royal Society